Unraveling the Code: Exploring DNA Structure and Function

Biology Grades High School 13:01 Video
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Lesson Description

This lesson explores the structure of DNA, its components, and its function as the carrier of genetic information. Students will learn about the bases, base pairing rules, and the double helix structure.

Video Resource

DNA | Biomolecules | MCAT | Khan Academy

Khan Academy

Duration: 13:01
Watch on YouTube

Key Concepts

  • DNA Structure: Double helix, sugar-phosphate backbone, nitrogenous bases (adenine, thymine, guanine, cytosine).
  • Complementary Base Pairing: Adenine pairs with thymine (A-T), guanine pairs with cytosine (G-C).
  • DNA Replication: The process by which DNA copies itself, utilizing complementary base pairing.

Learning Objectives

  • Students will be able to describe the structure of DNA, including its components and arrangement.
  • Students will be able to explain the base pairing rules in DNA and their significance.
  • Students will be able to outline the process of DNA replication and its dependence on complementary base pairing.

Educator Instructions

  • Introduction (5 mins)
    Begin by discussing inherited traits and how offspring resemble their parents. Briefly introduce Gregor Mendel and the historical understanding of inheritance before the discovery of DNA's structure.
  • Video Viewing (10 mins)
    Watch the Khan Academy video 'DNA | Biomolecules | MCAT | Khan Academy'. Instruct students to take notes on key terms and concepts presented in the video.
  • Discussion (10 mins)
    Engage students in a discussion about the video, focusing on the structure of DNA, the role of bases, and the significance of the double helix. Clarify any misconceptions.
  • Activity: DNA Model Building (15 mins)
    Students will work in groups to build a DNA model using provided materials (e.g., colored candies, straws, pipe cleaners). They should accurately represent the double helix, sugar-phosphate backbone, and complementary base pairing.
  • Wrap-up and Assessment (10 mins)
    Review the key concepts of DNA structure and replication. Administer the multiple-choice and fill-in-the-blank quizzes.

Interactive Exercises

  • DNA Base Pairing Game
    A matching game where students pair adenine with thymine and guanine with cytosine to reinforce understanding of complementary base pairing.

Discussion Questions

  • Why is the structure of DNA, particularly the double helix and base pairing, crucial for its function as the carrier of genetic information?
  • How does the process of DNA replication ensure that genetic information is accurately passed on to daughter cells?

Skills Developed

  • Critical Thinking
  • Model Building
  • Information Synthesis

Multiple Choice Questions

Question 1:

What are the four nitrogenous bases found in DNA?

Correct Answer: Adenine, Thymine, Guanine, Cytosine

Question 2:

Which base pairs with adenine in DNA?

Correct Answer: Thymine

Question 3:

What is the shape of a DNA molecule?

Correct Answer: Double helix

Question 4:

What is the sugar found in DNA called?

Correct Answer: Deoxyribose

Question 5:

The 'acid' part of deoxyribonucleic acid refers to which component of DNA?

Correct Answer: Phosphate group

Question 6:

What is the function of DNA replication?

Correct Answer: To copy DNA

Question 7:

How many chromosomes do human cells typically have?

Correct Answer: 46

Question 8:

Approximately how many base pairs are there in the human genome?

Correct Answer: 6 billion

Question 9:

What holds the two strands of DNA together?

Correct Answer: Hydrogen bonds

Question 10:

Who are credited with establishing the structure of DNA?

Correct Answer: Watson and Crick

Fill in the Blank Questions

Question 1:

The twisted ladder shape of DNA is called a __________.

Correct Answer: double helix

Question 2:

The sides of the DNA ladder are made of sugar and __________.

Correct Answer: phosphate

Question 3:

Guanine always pairs with __________ in DNA.

Correct Answer: cytosine

Question 4:

The process of copying DNA is called __________.

Correct Answer: replication

Question 5:

Each rung of the DNA ladder is composed of a pair of __________.

Correct Answer: bases

Question 6:

The full set of genetic information in an organism is called the __________.

Correct Answer: genome

Question 7:

DNA is found in the __________ of a cell.

Correct Answer: nucleus

Question 8:

Adenine and guanine are classified as __________.

Correct Answer: purines

Question 9:

Thymine and cytosine are classified as __________.

Correct Answer: pyrimidines

Question 10:

A segment of DNA that codes for a specific trait is called a __________.

Correct Answer: gene

Educational Standards

B.LS1.1:[Standard] Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins, which carry out the essential functions of life through systems of specialized cells. B.LS3.1:[Standard] Ask questions to clarify relationships about the role of DNA and chromosomes in coding the instructions for characteristic traits passed from parents to offspring.

Teaching Materials

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